(I am a programmer)
I would say that these bugs, minus performance, are trivial to fix.
The performance problem is probably non-trivial because unity is hyper ineffecient, maybe unity physics + gameobjects should be avoided in the first place.
I don't if it is supposed to be "late game", but I mean that bug/performance/data is preventing game progress/scaling-up with reasonable UX.
A. Peons are effectively capped at 16-20 (because player may easily lose more than half peons after earthquake, within seconds).
B. Earthquake freezes for seconds (and chrome prompts unresponding) at 10K or so.
C. A lv.6 catapult can incur a very visible stutter at destruction; any building beyond that will freeze for >=0.5 seconds.
D. Upgrade >=5K is very unlikely to pay back. Extra buildings/slots are expensive.
Late game is unplayably buggy:
1. Peons definitely get stuck at drop site/catapult (within a few seconds), if speed is upgraded;
2. Peons randomly permanently freezes (throw them does not help);
3. Peons definitely jump into hole at respawn (within a few minutes) (throw them does help);
4. Earthquake freezes for dozens of seconds;
5. Ballon does not respawn after building detroyed by stability;
6. High level building upgrades never pay back because stability drops way too fast;
(Desktop) Tons of error prints on console.
Most of the Ascension bonus don't make sense.
"Auto Cast LMB Skill": 5%*4 chance per attack is way too low; should be at least 5%*4 per frame or per enemy hit by attack (to compete with auto clicker).
"EXP Gain": +20%*4/10 is way too trivial; should be magnitudes higher. (exp requirement should not be exponential in first place)
"Keep Coin": 5%-40% is a complete joke; should be at least 90% (to allow accumulation of 5-10x).