This is just my opinion after playing some PvP TD games
- Loop
You and ur opp are facing an endless horde of enemies, which is stronger over time. There is a limit of how many enemies u can hold on the field. Enemies passes will be tp-ed to the start with the remaining HP. Whoever reaches the limit first loses. - Endless
You will face an endless horde of enemies. The rule is simple: survive as long as possible. You will get rewards based on how many waves u cleared. There is a leaderboard for top survivors and reward for them after the event ends. - Preparation
No gold on kill. Gold will be given every wave. Selling a tower gives u 90% value of that tower. Boosters are much less effective. You will have 10s to prepare the defense each wave.