It's really boring.

Take poker for example. Games last around an hour, maybe two at most. You have some control over your odds of winning based on bluffing, betting, all of that, there is the risk of losing everything you've put in and a chance of gaining many times what you put in out. The game takes some degree of skill to play.

The slime casino is the opposite of poker. If you want to have a shot at getting something cool you have to spend serious time there. So much time that it takes entire days of gambling to pull enough boxes to have a shot at winning. You have no control over the odds, beyond choosing your machine- which isn't labeled at all, and may or may not contain boxes in spite of resembling similar machines.

How I would improve the machines at a glance

1.) Remove the 200 crowns to gamble option, and the ability to buy slime coins for 200 cr each.
2.) Make the machine require 100 slime coins per pull.
3.) Provide a list of what the machine contains
4.) Increase rewards accordingly

Redesigning the wheels

Since the wheels now require real amounts of effort to play, they should have real amounts of reward designed to fit many players' ideas of what it should contain. Not everyone wants or can use a lockbox. Here's a few examples of what I mean-

Low risk box wheel:
10% Special boxes (E.G. Box 40N)
90% Normal boxes (E.G. Box 001, 002, 006, etc.)
Coins per box: 100
Coins per special box: 1000

High risk box wheel:
30% Special boxes
70% Empty
Coins per special box: 333.3

Low risk crown wheel:
1% High Jackpot (1 million crowns)
9% Low Jackpot (50K crowns)
90% Regular Payout (5K crowns)
Average expected value per slime coin spent: 190 crowns/slime coin

High risk crown wheel:
1.5% High Jackpot (1 million crowns)
13.5% Low Jackpot (100K crowns)
85% Empty (0 crowns)
Average expected value per slime coin spent: 217.5 crowns/slime coin

Key wheel:
33.3% Slime Key = worth 60K cr
66.7% Nothing
Average expected value in crowns: 200

Why I think this would work

Going full circle back to the criteria I laid out-

1. Time spent = low, you press gamble on your chosen wheel, you're done; think about this as excitement per hour....

2. Control over odds = high; it tells you vaguely what's in the box and you decide on what risk you take

3. Stakes = high; it takes a long time to farm 100 slime coins

4. Potential gains = very real; none of these are trivial

5. Skill = your choice of what wheel you choose and why. Not the biggest/best factor, but it's an improvement

So does my idea show promise? Please do comment on that, as I'm very interested.