Casino Night Zone (Sonic the Hedgehog 2)

"Sparkling neon lights and glittering gold fill the Casino with razzmatazz! Play the machines with Button A, B or C. Flip the levers and push down the springs to send Sonic reeling like a bouncing blue pinball!"

- Sonic the Hedgehog 2 manual description

Casino Night Zone is the fourth Zone in Sonic the Hedgehog 2. It is a huge city on neon colors on West Side Island, taking place during night time. As many other Zones in the game, Casino Night Zone consists of two standard Acts with a boss fight at the end of Act 2. In line with the pinball-themed level design, Casino Night Zone features various bouncy casino-themed gimmicks and slot machines, making it one of the most unique Zones in Sonic the Hedgehog 2.

Overview
Casino Night Zone take place in a huge, sprawling casino city during the night time. Most likely, the inspiration for the background and Zone's theme has been the Las Vegas Strip. In the background, numerous buildings are seen giving off many jaunty electric colors and even further into the background there are lines of skyscrapers. One of larger gambling houses are seen having flashing decorations with the words "Sonic", "Casino" and "Sega".

Casino Night Zone's dark-gold landmass is highly detailed and has flashing neon colors as well. Along with the many colorful details, there are small, rotating icons of Sonic and Tails adorning it. The ground here is covered in red and blue layers with many neon colored palm trees, blue poles, Casino signs and other decorations along the paths. There are also many neon signs saying "Sonic" and "Miles" floating in mid-air. On huge halls and in U-shaped gaps, there are large blue and yellow colored tables with red zigzag borders, where Slot Machines are usually placed.

Sections in the Zone's level design is heavily based on the pinball tables. As such, there are a huge amount of halls to utilize the playable characters as living pinball. Sometimes, the player has to curl into balls and then enter the pinball tables in order to progress in the Zone. Casino Night Zone also features many alternate routes. While lower parts of the Zone have more narrow pathways, the upper parts have more linear pathways. Regardless, there are often deep gaps between sections with many gimmicks to be utilized to either climb up or fall down.

Gameplay
Since the level design of Casino Night Zone is based of pinball tables, the player has to pass through huge halls or spin up and down along deep U-shaped gaps. Many of these sections in the Zone contain numerous bouncy objects and obstacles which are similar to real-life pinball machine components. Traditional bumpers with five-pointed stars give 10 points per hit, but will not give points after being hit ten times. There are also small Drop Targets which give 10 points. Once touching it, it will change the color three times (green, then yellow and then red) until it disappears completely. Other bumper obstacles include blue hexagonal bumpers (which move either left and right or stand in one place), red triangular bumpers and bouncy plates which are placed on walls, ceilings or at the sides. There are also three small horizontal bars, which each give 100 points.

In Casino Night Zone, there are two types of flippers, each of which function differently. Neon green and white flippers function like real-flippers and can be used to launch the playable character higher up. Orange and white colored flippers are pointing downwards and are usually located on the bottom of U-shaped gaps which automatically send the player backwards upon being touched.

One of the most prominent features in the Casino Night Zone are the slot machines which are placed above or in the middle of the pinball table sections. By getting into the hatch above or below the slot machine, the player can roll the slot machine and enter different combinations on the three wheel icons on it to get a certain reward (see all results here). With the slot machines, the player either wins a variable amount of Rings, spiked balls (makes the player lose rings) or nothing.

Blue colored shuttle loops in Casino Night Zone are heavily automated. The player usually has to spin through them from winding tunnels, where he/she has to utilize pinball shooters to build up enough speed to being launched through the winding tunnels or shuttle loops. There are also deep and narrow elevator sections, where the blue platform will go up or down. If there are two blue platforms when the player comes to one layer, he/she has to jump once to make another elevator platform rise up. There are several purple conveyor belts to pass over huge gaps. Rarely, there are also green blocks, which move as string from up, right and down. They will then disappear and appear on the other side to repeat the pattern.

Casino Night Zone does not feature huge amount of threat with the small exception being Crawl Badniks and few lines of spikes. However, there are huge blue cubic blocks, which function as platforms or crushers on narrow pathways.

Act 1
In the beginning of Act 1, the player can either fall down to the pinball table and the lower pathway or utilize the conveyor belt to choose the mid-pathway. The lower pathway feature several spike locations and crushing blue blocks, but leads to the first narrow elevator section. After that, the player will be launched by Pinball Shooters through winding tunnels to a section with bumper plates. Here, the player has to use the green flippers to aim at the blue blocks and use them as platforms to progress with the Act. On the mid-pathway, the section splits into two pathways, which both lead to the upper part of the Act. There, there is huge gaps which lead to the lower pathway. In part above the Act there are Rings and bumpers floating in the mid-air above bumper plates, which the player can reach by using green flippers.

From there, the player can fall down to the lower pathway or progress through the upper path by using green moving blocks. The lower pathway has three U-shaped gaps with the third one leading to the lower pathway, while the player can progress through the mid-pathway without using gaps. The lower pathway has a small hall with bumpers and bumper plates, and has a narrow elevator section leading to the pinball section. The upper and center pathway have two Slot Machines set above the Act. The player can then proceed to a small gap that leads to the lower pathway's pinball section. If the player manages to get bounced up by the hexagonal bumper, the player can reach another pinball section to the far right. Both pinball sections will eventually lead to the end of the Act by passing through the winding tunnel or being launched ahead by the green flipper.

Act 2
Act 2 starts out by entering a winding tunnel and then using a Pinball Shooter. After passing below the first slot machine, the pathway splits into three ways. The higher pathway can be reached by utilizing the green flippers to reach it, while the lower pathway go down from the mid-pathway, which goes through a pinball section and a route to the center pathway. Below the moving blue blocks, there is a hidden pathway behind the wall that has a narrow elevator going to the lowest point of the Act. This route contains amy sideways-moving blocks that can crush the player. Beginning from the upper pathway, there is a deep, narrow elevator hole that leads to the center pathway. While getting up from the lower pathway, the player can also reach to the center pathway as well this way.

Following the upper pathway can be challenging as the player has to bounce on bumpers, drop targets and pass green blocks over huge gaps. The lower pathway will eventuall unite with the center pathway, and after running over the first Star Post and falling down to the U-shaped gap, there are two right pathways to progress through the Act. Also, there is a hidden pathway behind the left wall that leads to another lower pathway. This path has a long hall with Rings, bumpers and bumper plates on ceilings and ground, while on the right side, there is another elevator section leading back to the center pathway. All pathways, including the upper and two center pathways will unite on this pathway and follow the another narrow elevator section and the last pinball section in the act. After going down and passing by the last Star Post, the player reaches the boss arena.

Boss
In this Zone's boss fight, Dr. Robotnik attacks with a claw-wielding machine and drops red bombs from a hatch on the underside. An electric field means this boss should not be attacked from below. Do not be tempted to use the flippers just because they're there. The trick for this boss is to turbo-dash your way up the walls of the pinball arena, and hit Robotnik by jumping off the walls on your way up. It is tricky, but this method is still less dangerous than attempting a flipper-based attack.

Trivia

 * According to Yuji Naka, Slot Machines are based on their experiences at casinos while they have been working in America.
 * Sometime in the game's early development, Casino Night Zone seem to have altered appearance as the Simon Wai prototype of Sonic the Hedgehog 2 shows this. While the level layout seem to be slightly similar, the overall appearance is different, as landmass features more pinkish coloring with French card symbols on them and the background is drastically different. In the prototype, the level is incomplete and the player can't complete the Zone.
 * One screenshot also shows that, the player could easily utilize the Spin Dash on Pinball Shooter tunnels, while this isn't possible in the final game.
 * In the mid-point of Casino Night Zone Act 1, if the player jumps down to the first U-shaped gap in the center pathway, he/she will find the hidden route behind the right wall with the 1-Up monitor.
 * In Casino Night Zone Act 2, when the player chooses the upper pathway, he/she can go to the left by launching the playable character to the purple conveyor belt and jump there to the left side of the gap. If the player jumps down from the left edge, he/she will find out a long string of horizontal bars, which will give huge amount of points by jumping in the string line.
 * Although it is hard to do, Tails can start acting oddly, as he can be found flying around on his Spin Jump animation while following Sonic. He will return to the normal, once he lands to the ground.