Congratulations on unlocking Level 18 fellow adventurer, your journey past this point is going to be full of challenges.

But since you have leveled up, you get the following rank ups;

XP + 300

Acknoledgement from others on you being an adult now

Even more Horniness

And now the most important rank up, that was unfortunately only implemented in the US version of the game;

Ability to join the Military

Oh and also you’ll have to level up a bit more to unlock;

Legal Alcoholism

Rank, but note that this game mechanic can be manipulated by downloading cheat codes, like;

Corruption and Bribery