It's a pretty big expansion to the original game! The character designs are cool and animations add something for the player to enjoy while playing the games. The fusion forms are all neat combinations of character traits.
I think that the wheel is still the best conceptually. It's clear to play, hard to win at 50, but still allows players with poor reaction times to win. The only thing I'd suggest is maybe having another type of zone that needs to be avoided and scaling the rewards faster since going from 40 to 50 is a big difference in difficulty for a fairly small reward.
The dice game doesn't really have a skill component but is the easiest because it gives the player double the chance of winning. My suggestion is to switch to 3 dice per character, and allow up to 2 of either yours or the opponent's to be rerolled for a small price. Double the total dice value if there are two of a kind, triple if three. This will add a fairly substantial strategic component to the game.
The pins are the most fun to mess with visually, but are by far the hardest to form a winning strategy. The only times I won was when I got really lucky after 5 minutes and hit the reward value before the balls fell down, and when I got a ball stuck inside of a wheel. This is a tough one to get right because either you accidently add a spot that guarantees a payout or make it nearly impossible to win, so my suggestion here would be to make parts of the pin maze move so that players can try to time their drops as the strategic component.
Perhaps the naked versions could be a reward for some other goal than getting enough money? For example, not missing the wheel's target zone 5 times in a row with a bet of 30 or more makes the bunny get naked, and she dresses up again if you miss. It can be a way to keep players more engaged, maybe there can even be naked fusions if both the challenge goal and money goal are met.
Sorry if this is too many suggestions all at once, I'm just brainstorming. It's a neat set of minigames with cool rewards, but changing some rules to allow skilled players to win more could be fun!