Vertical slot machines

1) Why vertical orientation has become a trend

User scenario: 90% of mobile sessions are held with one hand, in portrait mode.
Average session: 3-6 minutes → fast login and minimum screen flips are important.
Advertising and marketing: vertical formats are better integrated into social networks and stories, which increases CTR and reduces CPA.

2) UX and one-handed operation

Spin button: in the lower right zone ("thumb zone"), size ≥ 64 dp.
Bet and autogame: next to Spin, minimum distance to the finger.
Information block (balance, win, menu): in the upper third of the screen, does not interfere with the reels field.
Gestures:

• swipe-down = repeat bet,
• double-tap = fast spin,
• hold = turbo.

3) Drum and screen design

Vertical setup: 5 × 3 or 6 × 4 with adaptation to the portrait; minimizing top/bottom blank fields.
Animation: shortened vertical movements, spin time ≤ 2.2 seconds.
Focus: drums occupy ≥ 70% of the screen, CTA and status - ≤ 30%.
Bonuses and tutorials: superimposed on the top/bottom, do not close the rotation zone.

4) Technical optimization

Graphics: AVIF/WebP textures, Spine animations; Symbol preload for smooth scroll.
FPS: 60 stable, let's say folback up to 45 without noticeable lags.
Download: first run ≤ 2.5s, starter pack weight ≤ 25MB (native )/ ≤ 3MB (web).
Return from background: ≤ 300 ms without losing bet status.

5) Game math and pace

Spin: 1.8-2.2 seconds, turbo ≤ 1.0-1.2.
Mini-winnings: short flashes and vibration response, ≤ 0.5 seconds.
Bonuses: vertical mini-games ≤ 30 seconds.
Autospin: limits on time or number of spins.

6) Metrics for vertical automata

D1 retention: ≥ 40% with portrait UX.
Average session length: 5-10 spins, 3-5 minutes.
Repeated visit per day: ≥ 30%.
Crash-free sessions: ≥ 99,8%.
INP: ≤ 200ms (95th percentile).

7) Marketing benefits

Vertical machines fit perfectly into TikTok, Instagram Reels, YouTube Shorts.
Creatives of the 9:16 format increase CTR by 15-25% compared to horizontal.
Interactive demos (PWA) work without turning the screen, reduce outflow.

8) Vertical machine checklist

Spin and bet are available with one hand.
Spin ≤ 2.2 seconds, turbo ≤ 1.2 seconds.
First screen assets ≤ 3 MB (web )/ ≤ 25 MB (native).
Return from the background ≤ 300 ms.
D1 retention ≥ 40%, repeat visit ≥ 30%.
Gestures are supported (swipe, double-tap, hold).
Balance and bet readable at 200 nits brightness.

9) Withdrawal

Vertical slot machines are no longer a trend, but a 2025 standard. They respond to the natural behavior of mobile users, integrate into marketing channels and provide quick short sessions. Those providers who combine launch speed, one-handed ergonomics and honest retention metrics win.