Modified version for gta2:

First of all old school gtas like gta1 or gta2 don´t have any percent counters, unlike the 3d era and later games. It is more an "All Goals" instead of "100%". In some later gta games like SA or V however there are percentage counters, but not every side goal (like completing "beat the cock" missions) counts towards the actual percentage. In old school gtas it is a similiar case, because some goals are listed in the pause screen, while other possible side activities like delivering cars to cranes or getting all bonuses are not. So to avoid any confusion or other arbitrary stuff, only the goals listed in the pause screen should count towards "100%"!

The goals are:

• (Total/Gang) Missions Passed: Each unique mission needs to be completed. Bugs that have you get double mission completes for the same mission don´t mean that you can do one mission less.. and neither if the counter is broken and doesn´t add up the completed missions anymore. In the special rare case where you can get a "Job Failed!" and "Job Complete!" at nearly the same time which might break the mission counter somehow, the following is important: If it somehow screws the possibility of completing each unique mission not counting the mission where it happened, then your run is rip. ;)

• Kill Frenzies Completed: Each unique "Kill Frenzy" needs to be completed as the menu says. Unlike in the gta1 games the completion is a requirement for this goal to register.

• Tokens Collected: Each unique token which is depicted as a gta2 logo needs to be collected.

• Target Score: You need to at least reach the appointed score, which unlocks a blinking pink marker that points to the level exit. Since it is a level based game (where you are supposed to unlock next levels by having target score and then finishing the level), going to the pink marker and leaving town is an additional requirement, which marks the level as completed.