The train is the battlefield
Monster Train puts your fights on a moving tower. The tower has numbered floors stacked from bottom to top. Your units stand on floors. Enemies enter from the top and walk down toward your pyre at the bottom.
The pyre is your life total. Each enemy that reaches the bottom floor deals damage to it. Lose all pyre health and the run ends. Every decision you make exists to keep enemies away from that bottom floor.
A run is a sequence of battles
You do not fight everything at once. The run moves through acts, and each act is a chain of battles. Between battles you draft cards, take a relic, or visit a shop. The map shows the next few nodes so you can plan a route.
Most nodes are combat. Some offer card removal. Others give you a choice of rewards. The order you pick changes which cards and relics you collect, so route choice is a real decision, not decoration.
Each battle has a setup phase
Before a fight, you see the enemies and their floor positions. You then place your units and spells, using the energy you have. Units you place stay on their floor until they die. Spells resolve once and are gone.
This setup step is where most of the thinking happens. You decide who holds the front, who supports from the back, and which spell answers the biggest threat. A good setup wins fights before the first turn.
The turn loop
On each turn you spend energy to play cards. Units attack on their own floor or support nearby floors, depending on their design. Enemies advance one floor per turn unless something stops them.
When an enemy reaches the bottom, it hits the pyre. That is the only way you lose. Everything else, from spikes to daze to buffs, is a tool for slowing or stopping that descent.
The boss ends the act
Each act closes with a boss battle. Bosses bring a rule that changes the fight, such as extra floors or a punishing passive. Read that rule first. Then build a plan that answers it instead of hoping your deck is strong enough.
The final boss ends the run if you win. After that, endless mode keeps adding pressure. That is covered on the endless mode page.
What stays constant
The win condition never changes. Keep enemies off the bottom floor long enough to clear every battle. Clans, cards, and relics are the means. The shape of the problem is the same every run.
Next: Which clan to start with.