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.