I made a version of the game with an autosplitter (added to the resources).

The features:

• Practice mode - you can play the game, and immediately have the option to move between levels with the "+"/"-" keys. This can be used for practicing levels, or for IL runs.
• Tracking level times - each level will have a "level timer" that shows how much time you spent on it, along with a recorded WR time for that level. So you can always know how good you played that level after finishing it.
• Speedrun timer - shows the same time as the IGT during speedruns, but works better.
• Load timer - during the load between levels, a new timer will start ticking, up to 3 second. That way you can know when the next level will start.

After a speedrun is finished:

• Long loads removal - each load time should be exactly 3 seconds, but sometimes you might have random larger load times by a few frames. The "loadless" timer will tell you exactly what your time would be without those long loads (and you can also submit it to the leaderboards)
• A screen with several other stats for the speedrun, along with an overview of the level times.

The autosplitter is recommended to use during full-game speedruns, and is also required for IL runs. Read the game rules for more info about that.