Random Number Generation, or RNG, is a highly debated topic in almost every competitive video game genre.

In the context of lane-pushing arena battlers, RNG is typically minimized compared to card games or auto-battlers.
The Luck of the Draw
If your opponent rushes the bridge and all your cheap defensive counters are at the bottom of your deck, you lose the tower.

Professional players build their decks specifically to minimize the chances of a truly unplayable starting hand.
Always include at least two cheap defensive options.Cycle your cheapest cards in the back.Accept that sometimes you will lose to a lucky start. Unit Targeting and Pathfinding
While developers strive to make AI as predictable as possible, the physics engine can occasionally create chaotic results.

To counter this, veterans always place defensive buildings in exactly the same specific tiles to guarantee consistent pulls.
Game StyleRandomness ImpactDrafting GamesSkill comes from long-term statistical managementStandard Tower RushVery Low - Only the starting hand is randomized Accepting Randomness
Getting angry at a bad starting hand only causes you to make further mistakes and lose the match entirely.

Focus on improving your timing and placement, and let the RNG sort itself out in the long run.