Recently I've been simulating how long it takes to progress through the game in order to balance the levelling system.
I've done this by creating a file where I calculate the rough amount of time it takes to level up once (or several times), while taking in consideration timer and experience bonuses.
Through the use of an index and always assuming the best possible training method available, it was possible to get a close estimate of the time it will take to max out your skills. With this we realized that experience on higher levels was quite far-fetched, needing a significant boost.
Simulating this has helped us tweak the experience values and make the game more approachable overall. I can say that levelling up on Razor Trail Survivors requires some time and effort, but is also very rewarding as every few levels there will be new content to look forward to.
On a different note, lately we have been working on the game's wiki page. You may give it a peek here. Keep in mind this is still a work in progress and things remain subject to change.
That being said, we hope for it to become a great source of information for the geekier ones (such as us).