It is impossible to beat high levels w/o cheating.
For lots of gems: install an autoclicker and left it busy for a night.
For huge sum of money: save, close the game window, change your system time to 2099, then reopen the game and change the time back.
How to beat the final boss, lvl 75 (lvl 45 too!). 1. Split your jellies equally 50/50, then each 50 split 20/20, to capture all the barracks quickly. 2. Capture a lab, then a second lab (better with the superweapon). Always choose the way outside forts! To select multiple barracks at once, draw a square and click the destination. 3. Keep your lab(s) running; don’t allow opponent's lab to finish its red scale (green scale is not so dangerous). First, apply all upgrades to the lab, then make the superweapon (red button). If you see a large opponent's lab, capture it first and continue with both. Your goal is to capture both boss's forts with 100 jellies on each of them. 4. When you get control on both forts, send all the 200 jellies from them on the boss, when it has a low number (~30), and capture it. 5. The rest of the level is easy. Get all the labs for capturing the big forts. Try to regain all the barracks. The forts are conquered at the last turn: without feeding they won't grow.
 "The Splitting"){kind=icon}
 "Full Moon"){kind=icon}
 "Idle Mine"){kind=icon}
 "JellyGo!"){kind=icon}
 "Mario Big Bang 2"){kind=icon}
 "Submachine 2: the lighthouse"){kind=icon}